Retort-furnace.



No. 696,456. Patented Apr I, I902.

' n. LAIBD.

BETOBT FURNACE.

(Application filed Sept. 24, 1901.)

(no Model.)

Fl GL3.

UnTTnn STaTTs PATENT Tricia.

DAVID LAIRD, OF FORFAR, SCOTLAND.

RETORT-FURNACE.

SPEGEFIGATIQN forming part of Letters Patent No. 69 6,456, dated April 1, 1902. Application filed September 24, 1901. Serial No. 76,327. (1% model.)

To [ti/Z whom, it may concern:

Be it known that I, DAVID LAIRD, engineer and metallurgist, a subject of the King of Great Britain and Ireland, and a resident of Forfar, in the county of Forfar, Scotland have of separating precious metals from their ores.

My invention particularly relates to the construction of a furnace in which means are provided for the more uniform heating of the retort to prevent local burning and for supporting the retort on a solid base practically throughout its length instead of at each end only, as in present practice.

In the accompanying sheet of drawings, Figure 1 shows the improved furnace in sectional elevation. Fig. 2 is a plan thereof. Fig. 3 is an end view, and Figs. 4 to 8 detail views.

In carrying my invention into effect I provide a dome-shaped body of fire-clay (1, enveloped in a thin sheet-steel casing Z), bound with hoops c and having metallic end plates (Z, which may be suitably bolted together or secured to the body a of the furnace. The furnace at is formed with a chamber 6, at the bottom of which I arrange slabs f, of fireclay, which form abed or support for the retort 9. Below the fireelay bed fof the re tort is a flame-bed 71,,Wlll0h communicates, by means of branch passages t', with the spaces left'at the sides and roof of the retort g in the chamber c. This arrangement is shown in cross-section in Fig. 4, the section being taken on the line A B, Fig. 1. The retort is connected at j with the usual or a suitable condenser 70 and is closed by means of a door Z. A second door on, hinged at 0 to one of the end plates, is provided, which door is secured by means of swing-bolts p, pivoted to lugs q,

' carried by the end plate (Z, engaging with slots formed in lugs r on the door. (See Figs. 5 and 6.) To open the door, the nuts 3 are slackened and the swing-bolts p disengaged from the slots in the lugs r on the door, as will be understood. The door Z of the retort is provided with a packing of asbestos to form a gas-tight joint with the retort. This door Z is secured in a manner similar to the door m, as will be seen from an inspection of Figs. '7 and 8; butthe door is not hinged, but removed bodily. In case difficulty is experienced in effecting this the door Z is provided withtapped lugs I. Screwed rodsu are brought into engagement with the lugs 25, the rods passing through the bored-out lugs a on the flange of the retort g and bearing against the end plate d of the furnace. By rotating the screwed rods (1 the door l is screwed upon the rods and is thus forced off the retort.

To heat the retort, I provide a burner consisting of an air-blast nozzle 2; and liquid hydrocarbon drip-nozzle w. A flame of intense heat is produced and projected within the flame-bed h of the furnace by the pressure of air, which may be obtained from any suitable source. Instead of liquid hydrocarbon, hydrogen gas may be employed. The heat thus generated is imparted to the fire-clay bedfof the retort, which serves not only to support the retort practically throughout its length, but radiates and distributes the heat more effectually and prevents local burning of the retort at the point nearest the flame of the burner. The cross-passages t conduct the heated gases to the sides and roof of the chamber 0, so that the heat is quickly generated to decompose the amalgam, the volatilized mercury passing through the outlet 00 of the retort to the condenser 70. In order to still further regulate the heat of the furnace and insure as much as possible the uniform heating of the retort g, the chamber a and furnace-bed h are inclined toward the retort in the direction farthest from the burner to concentrate the heat. Further to assist this the bedfof fire-clay terminates before the end of the flame-bed h is reached, so that the hot gases may come into direct contact with the base of the retort.

A sight-hole z is provided at one or it might be at both sides of the furnace-body Ct to afford means for inspecting the interior of the furnace.

I declare that what I claim is- 1. In combination in a retort-furnace, a retort g, a dome Ct of fire-clay in which the retort is placed, said dome having below the retort an inclined flame-passage h, and around ICO the sides and upperpart of the retort a space e tapering toward the end of the retort, lateral passages i communicating between the flame-passage h and the space a fire-clay bedfbelow the retort upon which the same rests, said fire-clay bed being supported by the dome a, and a burner '0 w for liquid hyd roearbon or gas, and air under pressure, substantially as described.

2. In combination in a retort-furnace, a retort g, a doorl leading into retort, and a condenser k, a dome a of fire-clay in which the retort is placed, end plates (1 and door on pro- 

